C. A. Twigg ond M. V. TwiggL Erindale College University of Toronto Toronto 181, Canada
Centenary of the Death
of JUS~USVON Liebig
Justus von Liebia has been called the "father of oreanic chemistry." He is recognized as one of the great chemists of the nineteenth centurv whose work laid the foundation of organic chemistry. His claim to fame rests on three main aspects of his life and work-his original research published in more than two hundred papers; his teaching ability and the legacy he left in his gifted pupils; and his interest and efforts in teaching "chemistry to the layman:' Liehig began experimenting at an early age in the "laboratory" of his father, who sold pigments and related substances. He learned no chemistry at school, since it was not even recognized as a subject then, but it appealed to him even though his confession that he wanted to be a chemist was treated as a ioke bv his teachers and fellow students. After leaving schbol, ~ i k h was i ~ apprenticed to a pharmacist. and he continued his private experiments on the explosive fulminates. At the university i f Bonn and later at Erlangen, where he obtained his doctorate,Z he again found chemistry a neglected subject, and it was not until the end of 1822, when a t the age of 18 he went to Paris. that he received what he considered useful instmction in his chosen science. There, in collaboration with Gav-Lussac. he worked vew hard, makina further promess on 'the fulminates, and several papers &ncerniig them were read before the French Academy. Shortly afterwards, when it was realized that the fulminates and cyanates are isomeric (the first examples) Liebig and Friedrich Wohler (1800-821, who discovered and analyzed the cyanates, formed a life-long productive friendship. In 1824, when only twenty-one, Liebig was appointed Professor at Giessen. Here, till 1852, he spent the most prolific years of his life, and despite inadequate facilities and lack of money, made important contributions to chemistry. His perfection of a reliable, rapid method for the quantitative determination of carbon and hydrogen stimulated an interest in the analysis of organic compounds. and i t enabled the em~iricalformulas of manv compo&ds to be obtained. ~ e - i n t r o d u c e da number df useful analvtical procedures and made contributions to the hydrog& theory of acids. However, Liebig is best known for his extensive preparative work, the most important of which was with Wohler on the benzoyl radical. A series of compounds was prepared from benzaldehyde and each of these can be regarded as a derivative of the "compound radical" benzoyl (C6HsCO). At the time this was a most significant advance, and the development of the radical theory was an important stepping stone towards an understanding of organic chemistry. Liehig, who had been created Baron von Liebig in 1845, spent his later years as Professor in Munich, where be devoted his time largely to applied chemistry, in which he had wide interests, ranging over agricultural chemistry, the theory of fermentation, physiological chemistry, and more unusual fields such as the manufacture of bahy
foods and extract of meat. and a scheme to convert the sewage of London into usefui fertilizers. It was mainly in Giessen that Liebig devoted much time to teaching. ~ e f o i ehe established the laboratory there, there had been no real chemical teaching laboratory in Germany and very few anywhere, and it was perhaps one of his most important services to chemistry that he promoted the idea that systematic practical experience was vital to the study of a science. Although it has been said that he was not a model teacher by any means, his general enthusiasm inspired his students. He encouraged them to answer their own questions and to work things out for themselves. Liebig very soon had more would-be students than he could accommodate, and it is a measure of his success that so many who later became famous in their own right spent some time in his laboratory. In 1831 Liebig became co-editor of a journal in which much of his own work was published. When he died the journal was renamed Justus Liebigs Annalen der Chemie und Pharmazie, and a year later this was shortened to its present title by removing the last two words. Liebig was also an innovator in making his name, work, and chemistry in general known to the public a t large. In the wider sphere he did this by publishing his "Chemische Briefe," and locally by giving public lectures. His chemical letters were published in a newspaper and later appeared in book form. They were written in a clear style which provided a model for later writers of "popular chemistry." The public lectures were given in Munich, mainly on winter evenings, from 1853 onwards, and were usuallv accom~aniedbv ~ r a c t i c a demonstrations l and experiments. ~ u n i c hwaH proud of its famous Professor of Chemistrv, and the lecture hall was normally full to overflowing. Members of the Court were amongthe audience, and royalty attended later lectures. During one lecture Liebig demonstrated the burning of carbon disulfide in nitric oxide and accidentally caused an explosion (wrong
'Present address: The University Chemical Laboratory, Cambridge, England. 2His thesis was entitled "Uber dm Verhiiltnis der Mineralcherniezur Pflonrenchernie."
Justin
YO"
Liebig (taken from lilustrated London News. 62. 418 (1873)).
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gases?). Some members of the Royal party, and Liebig himself, were slightly injured. Women in particular, very few of whom had ever been taught any chemistry, enjoyed these lectures, and some of these talks gained a wider public when they were published as "Chemische Briefe." Other colleagues gave some of the lectures in the series, which were held during about ten weeks of the year. Liebig died one hundred years ago this year (April 18, 18731, one of the most important and influential chemists of the nineteenth century who, having found chemistry a little understood and unacknowledged subject, devoted a
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long and productive career to helping to make it a widely recognized and respected science. Bibliography Liebig, 3.. Bor., 23,817 (18801; ChemimlNows, 63,265,276 (18911. Hofmsnn. A. W.,"Tho Liie-work of Liebig." (Tho Farsday Iaefure 18751, Macmillan and Co.. Lmdon. 1876. Partington. J. R., "A H h o r y of Chernistry.l. Maemillan and Co. Lfd., London, 1964, vo1.4. Shenstone, W. A.. "Justus wn Liebig His Life end Work." C-ll and Co. Ltd., Lon. don, 1895. Van Klmster, H. S.,J. CHEM.EDUC., 34.27 11957). Volhard, J.. "Justus "on Liebig," Johann AmbrosiusBarth. Leipig, 1909.
